If you want to be a detective you might value the post highschool education. Out of the ones I've known, they tend to have a criminal justice degree. They drive different vehicles, interact with people in different contexts, and may have different pay grades.
Many (perhaps most) police departments require new cadets to be patrol officers for N years prior to being promoted to Detective. Once promoted to the equivalent rank, you still need an opening on a unit and it can be competitive from what I gather.
